231 wobbly?

wibbly · Frequent Visitor Joined: Dec 20, 2003 Posts: 315

I seem to be finding that, after first lock (showing 4 sats locked), the position shown by the 231 wobbles about a bit (causing TTN3 to snap to adjacent roads). Once 'settled down' all seems rock solid.

Is this someting anyone elase has seen

- With the 231?

- With other XTrac devices (V1 or V2?)

- With non-XT devices?

W

Dave · Posted: Mon Nov 22, 2004 8:19 pm Post subject:

You should be getting more than 4 sats. 4 sats are border line for getting a 3D fix, and this is what you will require for navigating. If you're only receiving 4 sats in-car, then you most probably have an athermic windscreen, which dampens GPS signals. Take the GPS outside the car and you'll see it increase (if I'm correct). Only way to resolve this is to change the windscreen of the car, or buy a Re-Rad antenna.

Check this link for Re-Rad Reviews

wibbly · Frequent Visitor Joined: Dec 20, 2003 Posts: 315

Soory, that's what I meant by 'settled down'. After a while (a few mins) I get 7-9 sats shown as locked on quite reliably, which is what I'd expect from a xTrack device.

Really I'm just asking if a 'wobbly' position is normal as the receiver initially gets a lock when powerd up - as opposed to a more stable (if still relatively inaccurate) position.

W

Skippy · Posted: Mon Nov 22, 2004 11:16 pm Post subject:

In my experience that is pretty normal. You might have 3 or 4 sats then lose one or two of them or the sats you do have a fix on may all be in the same area of the sky resulting in a poor quality positioning accuracy.

In this case your position jumps around, sometimes as much as a few hundred feet. Once you have got a good lock, your position stablises.
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Mapwalker · Occasional Visitor Joined: Nov 04, 2004 Posts: 35

I have the same experience with the Syson CF plus which I reprogrammed to XTrack v2. I use it with Ozi Explorer CE and in such a program you can see the 'wobbling' very well because it doesn't try to lock your position to a road. The first 5-10 minutes my track is wobbling around my walking-trail but it will stabilize when 6 or more sattellites are found.

Xtrack takes more time to get a good fix because it also tries to use satellites with weak signals, this is the reason it can find more satellites and it is able to keep a fix in dense forest! Xtrack v2 is somewhat better than v1 but it still is a bit slow, no problem at all when hiking but in a car Xtrack is not the best GPS-system.
Xtrack is much better for hiking in nature than any other GPS-system. I do own a Garmin 60CS and it can't compete with Xtrack in a forest.

wibbly · Frequent Visitor Joined: Dec 20, 2003 Posts: 315

Well, I'm now finding XT2 on the Holux in the car is working very well indeed (once it "settles" down)

W

Dave · Posted: Tue Nov 23, 2004 6:58 pm Post subject:

XT2.0.2 and specifically on the Holux GR-231 I find that once I receive the 3D fix (usually sub 1 minute) I'm usually receiving 7-9 sats and I don't see any 'wobble'.

If you are receiving around 4 sats then XT will still try and receive lower quality signals and this will create this sort of problem. The only way around that is not to use XT which means purchasing a non XT Receiver.

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